0100

0100 is a four-character string that can denote different numbers depending on numeral base and context. In base-2 (binary), 0100_2 equals 4 in decimal; as a 4-bit pattern it has the middle bit set (bit 2, if LSB is bit 0). In base-8 (octal), 0100_8 equals 64 decimal. In base-10 (decimal), 0100_10 equals 100 decimal; the leading zero is typically ignored in decimal notation. In base-16 (hexadecimal), 0x0100 equals 256 decimal; the digits 0 and 1 are valid hex digits.

In Unicode, hexadecimal code points are written as U+XXXX; the code point U+0100 produces the Latin capital letter A with macron (Ā). Thus, in hex notation, 0100 can refer to that code point in contexts that use hexadecimal notation for Unicode.

In computing, the string 0100 might appear as a bit pattern, a numeric literal, or part of a filename or identifier. Leading-zero notation often signals octal in older programming languages (for example, C and C++ historically treat numbers beginning with 0 as octal). Modern languages vary; some disallow such literals or require explicit base prefixes (0o for octal, 0x for hex).